The present invention relates to a shut-off valve which has a valve housing with a shutting wedge displaceable in the housing by a spindle transversely to a flow direction, a cover which closes an oval-like housing opening and has a sealing edge engaging with the housing edge and an outwardly extending pipe, and a locking screw arranged in the pipe and forming a spindle guide, a spindle sealing and a support for a spindle collar.
When a shut-off valve is provided with such a cover closure, it is no longer necessary to have flange connecting screws required for a flange housing hood, and the cover is loaded with a medium pressure by a sealing edge which engages from inside the curved housing edge, so that it is retained in its sealing condition. Since the cover is formed by engagement with the housing edge larger than the upper housing opening, it is tilted during mounting by at least 90.degree. and then in a certain inclined position is inserted friom above through the oval housing opening into the housing. After the turning of the cover to its mounting position it must be lifted to its abutment against the housing edge and then fixedly clamped with the housing.
The German Pat. No. 3,141,416 discloses a shut-off valve with the above described cover which abuts from inside against the housing edge. After insertion of the cover for further mounting the non-lifted spindle is first introduced into the housing and its threaded part is screwed into the shutting body. The locking screw must be screwed into the pipe of the cover until its abutment against the spindle collar. Then the threaded spindle is pulled back by actuation of the spindle head until after abutment of the shutting body against the housing seat the cover with the pipe and the locking screw is lifted and finally pressed to its clamping position with deformation of the cover sealing ring. In this position vertical semi-cylindrical grooves in the cover and in the housing edge form several hollow cylinders at both sides of the cover, and cylindrical pins which form locking elements for the cover are inserted into the hollow cylinders and secured against falling out by securing elements.
In the above mentioned known shut-off valve, the locking screw for mounting of the cover must be completely screwed-in and the spindle must be first screwed in and again screwed back, and high spindle forces are required for pressing the cover against the housing edge. Also, the insertion of the different locking pins into the hollow cylinder is time consuming so that mounting and locking of the cover in the housing head is expensive. Moreover, unloading of the cover seal after loosening of the spindle by the available play of the locking pins is unavoidable, so that untightness of the cover can take place.